four e qually spaced visor attachment points around the lens opening. Visors shall be at least seven ( 7) inches long for an eight ( 8) inch lens and at least 9½ inches long for a twelve ( 12)-inch lens. Visors shall be described as cutaway, tunnel, or full circle . All heads shall be supplied with tunnel visors, unless otherwise noted on the Plans or unless prior permission from the Division has been received. All new replacement signal heads at any one intersection shall have the same type as the existing visors supplied, unless otherwise specified on the Plans. Visors shall be designed with a downward tilt between 3½ degrees and 5 degrees, shall eliminate the escape of light from one indication to another, and with the optical unit, shall eliminate the return o f outside rays entering the unit from above the horizontal (known as sun phantom). The Signal Sections, all brackets, trunions and suspension devices shall be painted in accordance with ITE ( Institute Transportation Engineers ) Specifications. The inside of the signal section visors shall be flat black enamel to eliminate objectionable reflections. Non - Metallic signal sections must have a color impregnated finish and be the same color as the enameled sections. The inside of non -metallic visors must also be painted with a permanent flat black enamel or use other means to prevent reflections. The optical unit shall consist of the lamp, lampholder, reflector, lens gasket and lens, and shall be so designed that all light emitted by the unit passes through th e leans and so that any possibility of false indications is eliminated. The lampholder shall be of heat resisting material designed to properly position a medium screw base traffic signal lamp, with means to accommodate a lamp having light center 2 -7/16 i nches in length for the 60 -watt and 100 -watt series and three ( 3) inches in length for the 150 -watt series. The lampholder shall be provided with a lamp grip to prevent the lamp from working loose due to vibration. Provision shall be made on either the lampholder or the reflector holder to permit rotation of the lamp so that the lead -in wires are up and the lamp shall be retained securely in that position, but no change in position of the socket with respect to the optical center of the reflector shall oc cur. The metal portion of the lampholder shall be compatible with brass or copper. Each lampholder shall be provided with two coded No. 18 or larger lead wires, type TEW, 600 -watt, AWM fixture with 2/64 in ch, 221ºF rating thermoplastic insulation, securely fastened to the socket, and with sufficient length to reach the terminal block with the holder or door fully open. The thermoplastic insulation shall at minus 30 F be capable of being bent six times around a one ( 1) inch mandrel without damage to its insulating properties at rated voltage. A suitable terminal block or blocks shall be provided in the second section from the top or in each section of one -section heads. The terminal block shall have at least one section fo r each signal head section plus at least two additional sections per block. Terminal blocks shall be standard commercially available units. Reflectors shall be specular aluminum in accordance with the latest ITE Specifications and shall be mounted in a r eflector holder. The reflector holder shall provide a rigid reflector mounting to assure proper alignment between the lens and the reflector with the door closed. The reflector shall have a lampholder opening in the back. The reflector shall have a bead or flange on the outer edge to stiffen the reflector and insure its dimensional stability. The reflecting surface shall be totally free from flaws, scratches, defacements and mechanical distortion.
920 The lens gasket shall be a slotted circular neoprene ga sket specifically designed to exclude moisture, dust and road film. The optical unit shall be sealed to exclude moisture and dust. This may be accomplished in one of two ways:
reflector/lampholder interfaces shall be equipped with specially designed neoprene seals to completely seal the optical unit. The section must not accumulate water. ii. If the reflector and lampholder remain in the section when the door is opened, the entire section shall be made watertight and dust tight by a weatherproof neoprene gasket contained in a gasket groove in the door. The gasket shall seal against a raised bead in the section to provide the proper seal.
The lighted signal shall appear to be ill uminated over the entire visible lens surface without shadows when viewed from any angle up to 30 degrees each side of the optical axis horizontally and up to 45 degrees below the optical axis vertically. The required appearance, light distribution and candle power intensity from the complete assembled section shall meet latest revision of the ITE Specification. "A Standard for Adjustable Face Vehicle Traffic Control Signal Heads."
Trunnions, Brackets and Suspensions: All trunnions, b rackets and suspensions used for assembling and mounting vehicle traffic control signal heads shall be entirely weathertight without the use of externally applied sealants or caulking. The trunnions, brackets and suspensions shall be the same manufacturer as the signal heads. All tubular parts shall be 1½ in ch IPS (DN40) pipe. When hollow cast brackets or trunnions are used, they shall be of sufficient strength to support the maximum load imposed by the signal heads under all normal wind conditions. The lower support or connection between signal heads in a spanwire or mast -arm mounted signal may be an aluminum casting or stamping of suitable strength. Wire raceway areas within brackets, trunnions and suspensions shall be of adequate size to carry all ne cessary wires without crowding, and raceway surfaces shall be free of sharp edges or protrusions which might damage insulation on wires. Suspensions for mast -arm or span -wire mounting shall include a device to permit adjustment for proper vertical alignme nt of the signal head. Non-metallic trunnions, brackets and suspension parts previously approved by the
metallic signal heads and must have metallic reinforcement at p oints of anticipated wear. Reinforcing metal must be compatible with aluminum, steel and galvanized steel.
Backplates: All signal head assemblies so indicated on the Plans shall be provided with backplates designed to fit the combination of sections for each signal face. These backplates shall be fabricated from non -ferrous metal of gage to withstand distortion in 60 mph winds and shall be firmly attached to each signal face in such a manner as to withstand the above wind load and to permit the opening of any signal independent from the other doors in the signal face. Overhead signal heads shall have backplates with a five ( 5) inch border. Pedestal mounted signals shall have backplates with an eight (8) inch border. The backplates shall be finished wi th the best quality, oven -baked black enamel and shall comply with Federal Specifications TT -E-489.